import 'package:flutter/material.dart';

class NavigationBar extends StatefulWidget implements PreferredSizeWidget{
  NavigationBar({Key key,this.child}):super(key:key);

  final Widget child;

  @override
  Size get preferredSize {
    return new Size.fromHeight(44.0);
  }

  @override
  _NavigationBarState createState() => _NavigationBarState();
  
}

class _NavigationBarState extends State<NavigationBar>{
  Widget build(BuildContext context){
    return PreferredSize(
      preferredSize: Size.fromHeight(44),
      child: widget.child,
    );
  }
}